xfs: validate acl count

This prevents in-memory corruption and possible panics if the on-disk
ACL is badly corrupted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index b6c4b3795c4a..76e4266d2e7e 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -42,6 +42,8 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
         int count, i;
 
         count = be32_to_cpu(aclp->acl_cnt);
+        if (count > XFS_ACL_MAX_ENTRIES)
+                return ERR_PTR(-EFSCORRUPTED);
 
         acl = posix_acl_alloc(count, GFP_KERNEL);
         if (!acl)